Did not see your screenshots come through on the post, but the first problem may be that you're using WEP encryption. Try using WPA2 PSK. The high throughput and very high throughput (HT and VHT) data rates are no longer used if WEP is enabled as per Wi-Fi Alliance guidelines. The support for WEP is still there, but it'll likely only be supported at the legacy data rates, up to 54 Mbps. All 802.11n and 802.11ac shouldn't be using the HT/VHT data rates when WEP is used, and due to the nature of wifi and CSMA/CA operations, you're not going to get 54 Mbps when connecting at the 54 Mbps rate, but perhaps more like anywhere from 50% to 60% of that, which is about what you were seeing.
If you did still want to "wipe" the configuration and start over, it's probably easiest to remove the Z1 from the Dashboard network where it currently lives, delete the network, create a new network for the Z1, add the Z1 to that new network and paperclip reset the Z1 and it'll come back up in the new network with all the default configuration.